title: In vivo measurement of glycine with short echo-time 1H MRS in human brain at 7 T.
abstract: OBJECTIVE
  To determine whether glycine can be measured at 7 T in human brain with (1)H magnetic resonance spectroscopy (MRS).
  
  
  METHODS
  The glycine singlet is overlapped by the larger signal of myo-inositol. Density matrix simulations were performed to determine the TE at which the myo-inositol signal was reduced the most, following a single spin-echo excitation. (1)H MRS was performed on an actively shielded 7 T scanner, in five healthy volunteers.
  
  
  RESULTS
  At the TE of 30 ms, the myo-inositol signal intensity was substantially reduced. Quantification using LCModel yielded a glycine-to-creatine ratio of 0.14 +/- 0.01, with a Cramér-Rao lower bound (CRLB) of 7 +/- 1%. Furthermore, quantification of metabolites other than glycine was possible as well, with a CRLB mostly below 10%.
  
  
  CONCLUSIONS
  It is possible to detect glycine at 7 T in human brain, at the short TE of 30 ms with a single spin-echo excitation scheme.
authors.affiliation: Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. giulio.gambarota@epfl.ch
authors.forename: Giulio
authors.initials: G
authors.lastname: Gambarota
authors.forename: Ralf
authors.initials: R
authors.lastname: Mekle
authors.forename: Lijing
authors.initials: L
authors.lastname: Xin
authors.forename: Martin
authors.initials: M
authors.lastname: Hergt
authors.forename: Wietske
authors.initials: W
authors.lastname: van der Zwaag
authors.forename: Gunnar
authors.initials: G
authors.lastname: Krueger
authors.forename: Rolf
authors.initials: R
authors.lastname: Gruetter
mesh_terms: D000465:Algorithms; D001921:Brain / Q000378:metabolism*; D005998:Glycine / Q000032:analysis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D018377:Neurotransmitter Agents / Q000032:analysis*; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D018377:Neurotransmitter Agents; D011522:Protons; D005998:Glycine